Synthesis of arylnaphthoquinones and their reactions with o-substituted primary aromatic amines

Cycloaddition reaction of 2-aryl-1,4-benzoquinones 1a-d with a number of di fferent dienes, namely 2,3-dimethylbutadiene; 1,4-diphenylbutadiene and ant hracene yield 2-aryl-6,7-dimethyl-1,4-naphthoquinones 3a,b; 2,5,8-triphenyl -1,4-naphthoquinone 4 and 2-aryl-1,4,9,10-tetrahydro-9,10-o-benzoanthracene -1,4-dione 5, respectively were investigated. In addition, the cycloadditio n reaction of 2-aryl-1,4-benzoquinones 1d,e with 2,3-dimethylbutadiene was also investigated to yield 2-aryl-5,8-dihydro-6,7-dimethyl-1,4-naphthohydro quinones 2a,b. Cyclocondensation reactions of Diels-Alder adducts 2b, 3b, 5 a with ethylenediamine, o-substituted primary aromatic amines gave quinoxal ine, phenazine, phenoxazine and phenothiazine ocyclic derivatives 6-14.